The present invention relates to a new and improved construction of a container or container arrangement for loose or bulk goods and which is equipped with a device for the discharge or outfeed of the loose or bulk goods out of a lower outlet connection or the like.
The container arrangement of the present development comprises as the discharge device a discharge or outfeed element, for instance a discharge spiral rotatably arranged at the lower portion or region of the container. This discharge spiral extends by means of its outer end into a discharge or outlet connection and its inner end portion is rotatably mounted. A rotatable drive is provided for the discharge spiral. There is also provided a wheel holder device containing at least one loosening or opening wheel which is rotatably mounted above the discharge spiral within the container. The loosening or opening wheel serves for the opening or loosening of the portion of the loose or bulk material which is momentarily ready to be discharged or outfed. The axis of rotation of the loosening wheel forms at least approximately a right angle with the axis of rotation of the discharge spiral.
Such type of bulk good containers for bulk or loose goods or materials, such as powders, granulates, fibers and flocks, are well known in the art and, typically, possess at a lower portion or region thereof having a substantially U-shaped or V-shaped configuration a discharge or outfeed spiral, also commonly referred to in this art as a feed or conveyor screw or feed or conveyor worm. As a general rule, the discharge spirals are provided with a variable drive for adjusting the discharge capacity or output throughout a certain range. Such discharge spirals have an appearance similar to that of an at least approximately rigid helical spring, but also could be designed as a full blade worm with or without an axial shaft. These known bulk good containers are afflicted with the drawback that in the case of materials which flow with great difficulty there are formed material bridges or clumps over the discharge spiral, such material bridges precluding a continuous dosing of the loose or bulk goods. Directly above the discharge spiral the loose or bulk goods are compacted most intensively, so that their flow or transport behavior is poorest at that location. The hollow space below each material bridge does not allow any of the loose or bulk materials to flow therethrough, and thus tends to act similar to a foreign body. Even material bridges which have been desintegrated tend to usually reform.
In such type of bulk good containers there have already been installed loosening or opening devices in order to avoid these drawbacks. These loosening or opening devices are arranged concentrically about the axis of the discharge spiral. Other constructions of loosening or opening devices have the axis thereof located above the axis of rotation of the discharge spiral, usually parallel to the rotational axis of the discharge spiral. In such cases there can occur a power transmission from the spiral drive to the shaft of the loosening device. However, if the axis of the loosening device is disposed at right angles to the axis of the discharge spiral, then the loosening device must be provided with its own motor drive.
In the case of motor drives limitations are placed upon the change in their power output range. For high power outputs, as general rule, it is only possible to operate the drive motor at 200 revolutions per minute, since otherwise the loose or bulk goods no longer will travel into the outlet or discharge spiral and be reliably entrained. In the case of direct-current regulator drives there is thus possible a variation of maximum 1:20 to 1:30. For lower power outputs the range is limited to a rotational speed of at least 6 to 8 revolutions per minute, since otherwise there occurs a thrust-like ejection of the loose or bulk goods. Therefore, in order to obtain greater discharge outputs there have been proposed bulk good containers wherein the discharge or outlet connection is attached to a releaseable front plate and also the discharge spiral is releaseable and exchangeable. Consequently, one and the same bulk good container can be operated with different diameters of the discharge spirals, for instance in a range of 20 mm to 80 mm. Each discharge spiral is again operated at the rotational speed range governed by the rotary drive. However, there are desired much higher output capacities because during the dosing of loose or bulk materials, depending upon their properties, depending upon the humidity of the air, the product moisture content, the grain size distribution or the like, the effective discharge outputs can be quite different even for a given rotational speed range and for a given construction of the bulk good container. An output range which has been determined in the laboratory, during production however experiences unexpected large deviations. It is then necessary to shift to a much larger or much smaller dosing range for a given bulk good container for a predetermined field of application,
al speed regulation, rather only can be carried out with the described exchange of the discharge spirals.
All of the previously described bulk good containers are afflicted with the drawback that there is either provided an additional drive or an expensive power transmission system containing additional shaft throughpassage means, seals and so forth for the loosening device. There is known from, for instance, U.S. Pat. No. 1,960,778 a loose or bulk good container which does not require an additional power transmission or drive for the loosening device. Instead, the loosening device is installed within the bulk or loose material container with the axis perpendicular to the axis of the discharge spiral and the arrangement is constructed such that the discharge spiral drives the loosening device in accordance with the principle of a worm-bevel gear arrangement. Stated in another way, the loosening device itself is constructed such that it engages, like a gear, directly with the discharge spiral. However, this construction is limited to a certain diameter of the discharge spiral. Furthermore, the loosening device only can be dismantled by carrying out relatively complicated disassembly work, and there is not afforded the requisite accessibility for accomplishing a complete or thorough cleaning operation when the equipment is changed over so as to process a different product. Furthermore, it is not possible to exchange the discharge spiral for the purpose of obtaining greater output ranges with a discharge spiral having a larger or smaller external diameter because, then, the axial spacing of the discharge spiral and the loosening device as well as the module and so forth no longer would appropriately match one another and because the outlet or discharge connection is fixedly secured at the housing.
With a prior art bulk or loose good container similar to the last-mentioned state-of-the-art construction, and as disclosed for instance in U.S. Pat. No. 3,895,744, there is additionally required a stirrer or agitator device for avoiding the formation of material bridges. The agitator device must be driven by the loosening wheel. Apart from the previously mentioned drawbacks, with this prior art construction there is additionally present the equipment expenditure needed for the provision of the agitator device. The inclusion of such agitator device in such system design additionally renders more difficult, if not preventing, the dismantling and, thus, exchange of the discharge spiral.
An accommodation of the form and the arrangement of the loosening device with the presently known bulk good containers is therefore possible, if at all, only with an appreciable expenditure in time, labor and materials.